SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e9e18d5a69fcfff79da69214a1ed94a1ce77db09991badd3c9be3678d09efa7' 
  AND token = 'x3u1vc88Ok4PsM+Rw0XNP1Bz/zG7mpQxT1eafQeTQag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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