SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a584804a84d7016cc62d8c5f463e7c7b3a6536eb23ae312b2b63fa07887e944f' 
  AND token = 'MMifq42dL+iRzAngzxSIKzyrxiBfd0bkkovWWXVrou0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}