SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bc713e0234906bf9f00694921d032bac4b4d9dd6c51d5bac7101c7c8a839d38' 
  AND token = 'gzI1ym0ez8Vop+NUhwF1ChtjnH/xDwZZQFmZp2yWMdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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