SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '591613778d8729ebccb4d1d5158209b1ea4cd860c740134b65dff0ad813a28c1' 
  AND token = 'JBrJ/fT+oIE+wUxE/jFIlRAhjAZCRmFCq9FQTYMJWrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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