SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d91ad4ac0bd456bab7f02cdd68fed92fd7eebd46f63f0ea537ce926627aa2db' 
  AND token = 'yqnqdW3n5G+XpbSKJ//0pmJa2JZPdqYmHoFZFhh4bhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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