SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b821f93b971a3130d354d26aa64c1ad28cdbf4d60748161fd2a99339cf5830a' 
  AND token = 'o4SXeeAPvhGpksG+8UD+e+UKPFXbuWnMKJQVjZev8JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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