SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d79be67ffad47b3ef40ea845f8e805f6740161e586327ddbc9743df44d7a775' 
  AND token = 'IkUuBRS4UFY82S73PVrGDImMUS/zGLzoC6BaJRVousw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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