SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21bf3304e31fa066a67b864c7790d6d9191470189b476792c3926c4f4d9d4b08' 
  AND token = 'GNLtvrwFI6BcHGyhgXpB86UIiUwdGcpfsHsua8KVNoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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