SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ed5a281ae76f752b36e078b7326c98fe071913d52caef569f6506ff1959b118' 
  AND token = 'uPi73aU4wdXTRzYinlX3VmRQCBfQkuyTqIGs1N0Rz5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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