SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0803e0d4fa430c85b6778b653d497d17b1796116059d9e9b6f6e44d112b63fca' 
  AND token = '5yPOo2cr1pYy2nnX0U1sCyizkIK2LgDlOZ2ainWJswQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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