SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5278e13932212c79caa27eff1bd065ade652705e7cc1f38cb910195af9ec7d6f' 
  AND token = 'DyW6MELV6TgWrh70MT9LiidNnL0wyvkfO1qUwupasJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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