SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11e8da3caf74942eec164f625795507fc68db00094d396a27d3556017dbf9f9a' 
  AND token = 'j4ZnHnC32uTcYp6URvsvy8qXT++ZaDb+HN884W3wnnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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