SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7978aba99d2c056e1197258c659eddc6380de5ac12b6d50523f0c5edf849ecef' 
  AND token = 'muX2mwRfFJRN+/ilbWObGWNWev/Hoqfo0wy0fSpBp1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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