SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20a8243eb5197386ebfa44fc5de59fb0813ae8d2255014aba875d500f3204b28' 
  AND token = 'petDRpwvjwOBbMf9oURSF74DijbCBmgE0IWtOt1AGl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00102

JSON explain

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