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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b438e6eaaaf2a9a72867d3172a0b3672f7b7f2f59d4fb3db02bc07a79017b8a' 
  AND token = 'f0qeQk73LbHF0TiKSlhl7wWwigrcO8KFY44HDwgNfPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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