SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '049f5ea248d4a4914560e675ac9f352a77e63dad269fb68c34fc06381189166a' 
  AND token = 'l0F4X19/6HCg5miBJ7KBXlGcxYRDP91zBmbe7LZLwps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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