SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b49434bc86b6ced3371e59a6b5c545d379e34e3414ecfa964ebaee733aed05af' 
  AND token = 'jQZ8/qVNgOElZD2tbxETL3ZU5O/nt6gOg2S6R8rW4Uo=' 
  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"
    }
  }
}