SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd488c331276c67f97dda5b9a4ff37ede09f578b5b4c186ecb71fe5e70b594051' 
  AND token = 'qNfYB6wgeFRDaTgQtck+ghopYK1lhOMDFM1GzJuHxTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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