SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef1a98b35d27355d66e9fdfbf9317a7255827d95f9ca13b0ccd3943f6c5b8794' 
  AND token = 'J0no/5eRF/2hWU2iBU2wVfh+3Kyo0hzNCPJZfL0dEjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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