SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1300c1e5c9be2b8e4b5277a9a4834c7e4a6cc9cf29bd906355143b6330d7e2e0' 
  AND token = 'jTzVZvcsVjjOhmbBStEys+DYqP5opzptvknEg/KEppE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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