SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f6ee292b1b78ff8670012b1d649631583506644152da337e82928a850b6f70c' 
  AND token = 'JDk+CDYjKzEtp+4b2NmO2R4ZVtq/kEWKSXSWkJHn66A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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