SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02e52e1ea48533ac1a5947de8069d2cda6c7af5f4936b645813606463ee3ac85' 
  AND token = 'lcJnbQoTz9FtVEPtY38/jFe0k+IM5KFvEYkgheDcBXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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