SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f6d25099d99c47bfc7497bcf3cf4c36a692d25ffd1f6d5b4bd1dbd2596424c2' 
  AND token = 'yQ8thaQWKgN8EjDV4XTY/MlwmK20rLYvYlq1KUx+cu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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