SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40bd77914127394f86016b6de9d659710167d96ad61312def4ce4a6db838402c' 
  AND token = '4AOEbXLZJDhHXdNNEPLFQiC+lWxhh7hL6oeAXczBubY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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