SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b2e836aa327396c2f80e885ccbfe7fb3917416aab00654c3cb18dbc04931da' 
  AND token = 'uNvPwkQ0BEUXsW5QPPgwRPhS5pdX4BJLTWqV72F/PiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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