SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '88fe48735821a68971553267c946034b6f53e00dbc211c26c9763a704200184f' 
  AND token = 'SuI276Q02ZggQTAK0BcoNsJjfdJpkJzG2CAl3t34bBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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