SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7321bac0f425122c94ba091040a3fa22f1f4e583d018fde89d6c5a9485810852' 
  AND token = 'NKRbCTnnporXzkY32nXpcVdgF7fsWDaPTH5sDWBWsnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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