SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2e58b3fed954bf00fbcc0a5b443acd8de0a9b623a19feafe8e21aa5ab8db2f1' 
  AND token = 'nemi6Ds5itkpQZmxPevk0ImNaN9qXbpp7sJ1eo3wISc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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