SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66f6232f9b46b934b1408437aee0224163a4ae6b696a0dcf09f97686317862a5' 
  AND token = 'j6cyWP+kaA5hVR23S/5FEQs1mog8uAR0pxRZZPpBe8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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