SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14030b1d3a0900bbe059a552c17a640658121e3a4aa09cf6febd3a30ed8a8199' 
  AND token = '0I5VGlTMzq1XZMopt989qgI7+7kut7Ff+K7wq25US7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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