SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1ae48d3be6d8d8d9e6d43b95f816a4791a96cd437887a82671c360d010ab95e' 
  AND token = 'fpj1CvVlUuFbKwYGZAhrzYHXyHrpG0rwpk7NYnG5c9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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