SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2447070b6cc39eacedf296de2fc8a45e334716c56f8385f3d77988f478ad8650' 
  AND token = '4pt6DVUhRxLHO01nLyf8YBvXXsNemAHQGOhKoBmNKGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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