SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdb58c92e06091b49912a8a6a51565c3a155a21abf346e1c37eb06a5ee5a56fd' 
  AND token = 'QIFDIzGvsENw/YnRcqX+ygmegTErpsXX6uaikqQjFqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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