SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38a091e64faae282bef0ba72a0cdde5a0e3a96a3efa252018ec88fdf729a6d97' 
  AND token = 'VLOTiYNG84ZDzRPywmf/xT07Vt/jkFG3k1LIoIMTkU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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