SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b55fb8f76abb26a255e6ae6ab43e9828bdfbfddeda2d076b1c49bdb2cddfb90c' 
  AND token = '3HXdUKVSbj9VOi06Xj746DDIA+2lY2PM2Rv1NXHKMlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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