SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e40068a9771ef423fb686546cd6ce4a752b048de9593adfe5b4b52dc3c9bc097' 
  AND token = 'U/5TXT+hjcXvvC5hCAYKEiUVv7YWGEmjOKK9QTDZyhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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