SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81377d2bdb784c9800f88483a9803d4efb7c970ab8cc26510ef174cfc7774223' 
  AND token = '4G5vMDbKSEhyANNQDJ6yFR4U550hSUHnFkGHUee+SGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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