SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394146abac648d1cd92d53b05fd17750b79c85f9f448a6e4206b28035c641d36' 
  AND token = 'deYAhI7YuoHKF+OpiDaL7Jx9BCK4pnwePH22yo7UDHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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