SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37cfaec7ef73cf02aea03bde24a967f1c0e3ba1bd5f1cb89bb1bd65bc2314d6f' 
  AND token = 'qSZat1agOeZiH1v5UDldeGMpnltpyuCeOP9yEvYHMNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}