SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b1df294e1f2dd4d599c468d354a5b34a48f490e13d467e375f926fb9184b99d' 
  AND token = 'YVjoyggvkUud3KOjsyjPeE4cASC97JmxhG4quRZLVyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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