SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '040210e6359076f5885769a1939f1771fd0236fb87039914ed8879dfff5ec988' 
  AND token = 'jX6FJHWJYLddmsSdiLN9qBrPBA85yApXqlZpqySPGhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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