SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45392cdeb369add5315f30a89b2ba291be12aef76bfe2c51e87dd099e1847ad7' 
  AND token = 'uJL/HjbOlCXRLNpFhumrxv27PXMW/hxJP0MiuC+LzUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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