SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaac3c6ed51b716a29b94526310fe8011d1bcbe5caf1857e30110a29ee4a259a' 
  AND token = 'pd847yodpog8p3R6uvSVTOg76plqbwB0pKPpLfTK0PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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