SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ad5ec301f11a21cb38815689f739d608e4e89147e865af374130ab300fee97c' 
  AND token = 'E3gLYMCvIRZ9Ya4deHDzaEDutnuq82PFnXuavQW84i8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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