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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '627a165fd29da35f18cd6bbf3c91c2943798b982f3ce0585ad0dd6320bc2a049' 
  AND token = 'u2E9hlqFpkMahe5drRcp1nJr5XkAzlA+qRypnawqCcQ=' 
  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"
    }
  }
}