SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '332ecc760878b116eb7afe69bfeeb3f9c5625fa872de8be894f99d5bce821d18' 
  AND token = 'rfqGwsmFJ/fr+9vtis9F0sqbh7hVVKUpD16ffLYh+pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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