SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61f4c90fabe07a60a172e28da9f56fb96c448e6069750da998620e4aa22e6b72' 
  AND token = 'qYy+RmPv3ZsDHIjhlY4McrTPEkjBhGP6Ru4OifxUXiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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