SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ae6a8e026b1b142bdef392df07b3fafba492ccb571f1542f15efbe417746112' 
  AND token = '0UlVJebkcNtbSau/JDUvtOfhUh57qRKjHOv8wiHNZT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}