SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fcb548341cc9f9b12cb4b6485ac9c25e18c88d8a71dfbda9dd2623f53e0425c5' 
  AND token = 'SqQsLdJ7jC9Ar1T/txrVki6gijQxGwe8fLEJ6iwlotU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}