SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eb16b1d2486698074024a873c3c617f5533e26ffe94a23cb3399698de391638' 
  AND token = 'WWqcv367Tzz8tyUMkV/sUFKoqM8dzMq0iKo4BYH3KWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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