SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3427023ebff1ec798471fd621682b798d1b609eaa94edb163eef3cd01731381' 
  AND token = 'Na82iY6eEJeASQbe3c/Puu75u8V88FYnhKNEKbPmoCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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