SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e8be3822947d2562e149615fdf6d81ae4dab481c395865716623e1ba2bf1166' 
  AND token = 'diSIlAExlclfplMd7h+8BiINGC55i3d0qK4XGqzpyuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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