SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01540552fda94d7664638daab2ee55444133c0cbfb586dfe0c5fad3d8f5ec374' 
  AND token = 'xfvJ+5tmd+MhN5c43+k0k+NYB8hXw7nd8Z6PbC+iDQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}