SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4aebcfe332f73782d9761b79d32c81c315ba882f529733eba9860cd94738b6' 
  AND token = 'zBoDFUk2AeqiO9YUuLVGesmIvDAQhS2rETB0bOYIUMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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