SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02cd4e99428d9f4c92d84041bb1ebd171462dcf30b3b66d28b2cad70193a3ff8' 
  AND token = 'DS6aEGhJh0qYpuJG3gxCMQTmdQY5A5d+hwzYNCZw2KU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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