SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f000b50e33b838efbe873c16993e8292934bca165a1a2a9af727c9016fa00cef' 
  AND token = '2ukqEVpmYonlNcfUCImsaX0LBcx3jJFZOWYCb8gxJ5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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