SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a70ff89694fd3beb7944489f67dc06578248b10712ef90e351ace3cf979a3aa5' 
  AND token = 'VO4cbUaaCsUSPfLWNgO0SSVhp/0JQv1Uerzpltdt+cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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