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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dd087ff6165b5862057c0b114524d3be9d25672f436011a2a86a7c3927dcb9c' 
  AND token = 'a1ONtYPz1kE+pmgxu2rau2zbCwPU125+SrRmB/6Stlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}