SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17ca049780d43f6d3d8979fc1483699363604ab00b5018504e831579d205457' 
  AND token = 'OrpgMWtRReLgRHCVw8piUaPVG0yLTWzdCo1KvVNlAaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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