SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c17f0beb79c5e346511371d100373df5c60378a3a7a88f6cf86f956fa604d62' 
  AND token = 'wmt6laQyBmnKmwVBUD2xiK3InZV9gSgBhJPJFys+e5E=' 
  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"
    }
  }
}