SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c428bd1a814132fdae12f5c67679445d3d657026aa313b94b702db1f81d4734' 
  AND token = 'ZvXPmaHoah/Qg+4TibbAG5FZmEGYq7tixUogTruYhf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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