SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad47200434af89f2920836e944affafc1fd527ffc01a9dcce5ff2a854f2db63d' 
  AND token = 'fBxWnUecFPfh+GzQ6imbeYquNs2PQ9PWay5Zuv4ZKjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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